Current wireless communication systems transmit incoming call notifications through paging messages from the base stations to mobile communication devices within their coverage areas, such as the GSM. To maintain the synchronization between the base stations and the mobile communication devices, the base stations periodically transmit dummy paging messages that do not contain actual information. In fact, most of the messages sent from the base stations are dummy messages.
FIG. 1 illustrates a partial functional block of a communication system, wherein a transmission end 10 is a transmitter in a base station and a receiving end 20 is a receiver in a mobile communication system. In GSM systems, the original message code, of whether an actual paging message or a dummy message, contains 228 bits of information. The encoder 12 encodes the original message code into 456 bits of information through convolution coding at ½ bit rate. The interleaver 14 arranges the encoded information into four information bursts each representing 114 bits of information. The arranged bursts then are transmitted sequentially in a form of radio frequency (RF) signals after being mapped and modulated respectively by mapping unit 16 and modulation unit 18.
A receiving end 20 and an RF receiver 21 receive the corresponding signals from the four information bursts sequentially. The received signals are then restored into 228 bits of restored code after being demodulated by a demodulator 22, removed channel response by a channel equalizer 23, rearranged by a deinterleaver 24 and decoded by a decoder 25. The posterior circuit then determines if the resulted restored code is an actual paging message or a dummy message to proceed with corresponding processes. As shown in FIG. 1, the outputted signals from the demodulator 22 are also directed to a channel estimation unit 26, resulting necessary channel impulse response information for the channel equalizer 23.
In theory, the receiving end 20 determines if the paging message is a dummy message only or an actual message after having completely received all four information bursts and having them reconstructed into restored codes. However, if a paging message is determined as being a dummy message, it signifies that none of the four bursts contains actual message in regards to the call information. For a mobile communication device that emphasizes on the standby time, such unnecessary power spending for transmission of mass void information is considered intolerable.